1. Field of the Invention
The present invention relates to a compact and easily maintainable image recording apparatus using an electrophotographic technique.
2. Description of the Prior Art
Recording apparatuses are widely used in various fields, particularly in the field of the so-called "office automation", and are now required to offer a good quality of printing performance and finely recorded images. An image recording apparatus of a type using laser beams has been developed to meet such a requirement and the use thereof is now spreading. FIG. 19 shows such an image recording apparatus.
In FIG. 19, a reference number 1 generally indicates the image recording apparatus. There are provided a paper feeding system 2, a process system 3 for performing an electrophotographic process, a fixing system 4 and an optical system 5 in a main body 1a of the apparatus 1. The paper feeding, system 2 takes up paper sheets 7 stacked on a paper tray 6 one by one and conveys the sheet 7 taken up to the process system 3. The process system 3 includes a photosensitive drum 8, two chargers 9 and 10, a developer 11 and a cleaner 12. In the process system 3, the charger 9 provides the photosensitive drum 8 with negative charges and laser beams coming from the optical system 5 form an electrostatic latent image on the photosensitive drum 8. The developer 11 has a magnetic roller 15 to which toner 14 fed from a toner casing 16 adheres. The toner 14 on the magnetic roller 15 is attracted to the photosensitive drum 8, the electrostatic latent image thereby developing. The sheet 7 conveyed to the process system 3 is provided with positive charges by the charger 10 and then the toner 14 adhering to the photosensitive drum 8 are transferred to the sheet 7.
After the toner 14 is transferred to the sheet 7, and residual toner 14 is removed from the photosensitive drum 8 by the cleaner 12. The cleaner 12 has a silicon rubber plate 17 to contact the photosensitive drum 8 along the width direction. This silicon rubber plate 17 scrapes the residual toner 14 from the photosensitive drum 8. The scraped toner 14 is gathered in a used-toner casing 18.
The sheet 7 with the toner 14 is sent to the fixing system 4, where the toner 14 is thermally fixed. Thereafter, the sheet 7 is discharged to a delivery tray.
The photosensitive drum 8, charger 9, developer 11, cleaner 12, toner casing 16 and used-toner casing 18 are integrated in a housing, formed of resin or other materials as a "process unit 20" which is replaceable when the toner 14 in the toner casing 16 has run short. This makes maintenance operations, which are generally complicated and troublesome, as simple as possible.
By the way, compactness or size reduction is generally required in various kinds of apparatuses. This permits economic use of space in offices or other places for installation of the apparatuses. The above conventional image recording apparatus 1 is, however, structurally difficult to make compact for the following reasons.
In the image recording apparatus 1, a total occupied area in a paper conveyance direction of the paper feeding system 2, the process system 3, and the fixing system 4 establishes the installation size of the image recording apparatus 1, more specifically, of the main body 1a. Although the image recording apparatus 1 can be theoretically made smaller by decreasing the area occupied by the respective systems, there is a limit in reducing the size of each system and, as a matter of fact, it is almost impossible to make the aforementioned conventional image recording apparatus smaller.
It is to be noted that because the paper tray 6 and the delivery tray 19, which are separate members, are mounted to the main body 1a for an actual use of the image recording device 1, an additional space for installing both members 6 and 19 is also required.